1. Field of the Invention
This invention relates to a fluid and chemical mixture injection apparatus that injects a calibrated amount of chemical into a fluid flow exiting the apparatus so that the ratio of chemical to fluid flow exiting the apparatus is not dependent on the pressure of a fluid supplied to the apparatus.
2. Description of Related Art
In the past, various configurations of chemical dispensers have been used to dispense soaps, perfumes, fertilizers, insecticides and numerous other liquids. The pressure of the fluid to be mixed with the chemical very often affected the ratio of chemical to the fluid with which it was to be mixed. This often led to an uneven application of liquid. If the correct ratio was critical, incorrect applications were costly and wasteful. Some of these devices also allowed the chemical to backflow into the water source thus contaminating the water source.
U.S. Pat. No. 1,297,622 to A. Whittaker on Mar. 18, 1919 shows a sprayer apparatus with a three way valve to control the amount of chemical entering the hose and mixing with the water.
U.S. Pat. No. 1,736,803 to T. C. Shields, et. al. on Nov. 26, 1929 describes a shower that has a piston supplying pressure to a chemical but lacks a calibrated or accurate flow regulator and there is no backflow protection between the pistons.
U.S. Pat. No. 2,323,618 to O. Ottoson on July 6, 1940 for a spray gun has a simple three way valve that restricts the flow of the chemical and has a series of evenly spaced numbers to allow the user to remember where the valve was placed. As chemical is used, water forces a piston down to reduce air pockets.
U.S. Pat. No. 3,200,840 to J. H. Watts on Aug. 17, 1965 for a chemical injector for a boiler controls the flow of chemical into the boiler by restricting the length of travel of the piston.
U.S. Pat. No. 4,047,541 to Julien Mercier, et al on Sept. 13, 1977 for a liquid dispenser for a shower head uses a hose attached to the water supply pipe with a pinching spring clip to restrict the flow of water to the top of a piston that forces liquid into a water stream.